The present invention relates generally to a PC surround sound mixing circuit, and more particularly to a circuit configured to receive a plurality of audio signals (both from a PC and other sources), perform a function on the audio signals, and generate a single surround sound output signal having a plurality of output channels from the input signals.
With the introduction of DVD, CD and other audio sources into the PC market, there is a trend to develop new game titles and movies which deploy the surround sound format having three or more audio channels in order to give a realistic, surround sound environment to the PC user. A typical encoded surround sound signal may utilize coding schemes such as Dolby AC-3, Sony Dynamic Digital Sound, Digital Theater Systems, or the like.
However, even though surround encoding is used, many of the PC games still will use common data signals (e.g., WAV, MIDI, AIFF, AU, MP3, or the like) to create effects such as guns shooting, fight noises, or dialogue. Currently, there are two types of mixers available in the market which can be used to play these games. These mixers typically are found in computer sound cards which are configured to receive two sound channels and mix the sound channel with the PC audio signals (i.e., WAV, MIDI, AIFF, AU, MP3, etc.) However, the two line in channels to the computer sound cards only can extract two channels of the surround sound signal, and the mixing of the channels with the PC audio signals can only provide a two channel output. Thus, the surround sound signal is essentially lost.
In addition, a number of surround sound receivers can receive input signals other than surround sound signals. These surround sound receivers typically can decode surround sound signals while also receiving a plurality of channel input signals, for example six-channels, from another source. However, these receivers only can play the decoded surround signal or the signal input from another source. They cannot play both at the same time (i.e., they cannot mix the signal). Thus, a user interface is needed to switch from one signal source to the other. For example, one signal into the receiver may be an encoded surround sound signal from a DVD device, while the other signal into the receiver may be a PC audio signal. Thus, the user must switch from the surround sound signal when a game is playing standard surround signals (i.e., from the DVD device) to common data signals when a game is playing interactive signals, such as guns shooting or fight noises.
Therefore, if a PC user wants to enjoy both common data and surround sound signals simultaneously while playing PC games without any user interference, the PC user must connect the PC data output to special equipment which up-mixes the two-channel PC audio data signal to a six-channel signal which can be played on a six speaker system. Simultaneously, additional equipment is needed to decode the surround signal from the DVD device and load it to six other speakers.
Thus, there is no device which can receive both the surround signal and the PC signal and combine the two into a single surround sound signal.
Accordingly, it is an advantage of the present invention to provide a PC surround sound mixer apparatus which overcomes the shortcomings of the prior art.
Another advantage of the present invention is that a PC surround sound mixer can receive a plurality of audio input signals from one or more audio sources and generate a single audio surround sound output signal from the plurality of input signals.
Yet another advantage of the present invention is that a PC surround sound mixer is configured to play games, movies, and other applications which include at least one audio signal encoded with a surround sound signal.
Still another advantage of the present invention is that a PC surround sound mixer can mix an encoded surround sound signal from one source with one or more audio signals from one or more other sources to generate a single multi-channel surround sound signal.
Still another advantage of the present invention is that a PC surround sound mixer can receive a plurality of signals, each having one or more audio signal channels and generate a multi-channel surround sound output signal by selecting different audio signal channels from the different input signals.
The above and other advantages of the present invention are carried out in one form by a PC surround sound mixer configured to mix a PC audio signal having one or more audio signal channels with an audio surround sound signal having one or more audio surround sound channels, and generate a PC surround sound output signal having at least three PC surround sound output channels.
In accordance with one embodiment of the present invention, a PC audio mixer, which is configured to mix a PC audio signal having one or more PC audio signal channels with an audio surround sound signal having three (3) or more audio surround channels, may have one or more function generators that are audio signal modulators configured to modulate at least one of the PC audio signal channels with at least one of the audio surround sound channels. The audio signal modulator generates at least one of the output channels, which is a modulation of at least one of the PC audio signal channels with at least one of the surround sound channels. Conversely, the audio signal modulator may be configured to modulate at least one of the audio surround sound channels with at least one of the PC audio signal channels. The audio signal modulator generates at least one of the output channels, which is a modulation of at least one of the surround sound channels with at least one of the PC audio signal channels.
In addition, the PC surround sound mixer may be configured to receive analog signals, digital signals, or a combination of both. The one or more audio signal mixers used in the PC surround sound mixer may be digital signal mixers or analog signal mixers. If the audio signal mixers are analog signal mixers, and one or more of the audio input signals are digital in form, the audio input signals first will pass through a digital-to-analog converter before passing to the audio signal mixers. Similarly, if the audio signal mixers are digital signal mixers, and one or more of the audio input signals are in analog form, the input signal first will pass through an analog-to-digital converter before passing to the digital audio signal mixer.